JPH01250347A - Transportation and storage of maleimides solution in acrylonitrile - Google Patents

Abstract

PURPOSE:To safely and simply transport and store the title solution with a easy handling and without the denaturation of maleimide, by adding an inert compound of a specific molecular weight and a polymerization inhibitor to the solution. CONSTITUTION:An acrylonitrile solution containing maleimides used as a starting substance of resins, medicines, or agrochemicals is handled in the presence of a compound of over 100 molecular weight and inert to the maleimides and acrylonitrile in the solution, such as 2-anilino-N-phenylsuccinimide (molecular weight: 266) and a polymerization inhibitor such as p-methoxyphenol. Thus, the maleimides are transported and stored stably and safely without precipitation of maleimides of high concentration even at low temperature. The transportation and storage costs are lowered and the solution gives the final polymerization products of high maleimides contents.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for transporting or storing maleimides as a solution of acrylonitrile.

Maleimides are compounds useful as raw materials for resins, medicines, agricultural chemicals, etc., and the present invention provides a method for transporting and storing maleimides that is easy to handle, safe, and simple.

[Conventional technology]

Conventionally, maleimides that are solid at room temperature have generally been handled in the form of powder, flakes, tablets, and the like. However, such a form of 7reimide contains fine powder of maleimide.

(During the transfer of such solid maleimides, the maleimides are pulverized and a large amount of fine powder of maleimides is generated.

Maleimides themselves are irritating to the human body, and have undesirable properties such as irritating the nasal passages and throat, causing coughing and sneezing when inhaled in fine powder, and causing inflammation if left in contact with the skin. ing. Therefore, when handling maleimides containing such fine powder, strict care must be taken to avoid contact with the skin as much as possible.

Therefore, a great deal of effort is required to prevent the generation of fine powder as much as possible during the transfer of 17-reimides, and to remove fine powder from the maleimides after transfer.

Furthermore, solid substances are often transported by filling paper bags, drums, containers, etc., but in these cases, contact between maleimides and the human body is unavoidable, and the human body may be exposed to maleimides. Adhesion of fine powder is inevitable.

In addition, in order to avoid contact with the human body, it is difficult to transfer solid substances through piping, and the inside of the pipe may become clogged during piping transfer. Strict restrictions are imposed on size, specific gravity, etc.

As described above, it must be said that there are many difficult problems in the method of transporting or transporting maleimides which are solid at room temperature. The same thing can be said about the storage method.

On the other hand, a method for transporting, transporting or storing maleimides as a solution of acrylonitrile was disclosed in Japanese Patent Application Laid-Open No. 62-1261.
It is disclosed in Publication No. 67.

This method can be said to be an excellent method in that it can solve the above-mentioned problems when dealing with maleimides.

Usually, acrylonitrile solutions of maleimides are transported using tank trucks, bulk containers, tank wagons, tankers, or the like.

However, it is said that transferring or transporting maleimides in the form of such a 7-crylonitrile solution is not an economical method because the transport efficiency of maleimides is poor, or in other words, the transportation cost per unit weight of maleimides is high. There were drawbacks.

Therefore, in order to reduce the transportation cost as much as possible, it is possible to transport it in the form of a highly concentrated acrylonitrile solution, but by increasing the concentration of 7reimides in the acrylonitrile solution, maleimides can easily precipitate from the acrylonitrile solution. It has also been pointed out that the entire solution turns into a slurry or solidifies, making it even more difficult to handle in terms of transportation or storage.

In addition, in order to prevent the precipitation of maleimides, it is necessary to keep the tanks, transport piping, valves, etc. used for transporting or storing acrylonitrile solutions at high temperatures, which requires very complicated and expensive equipment. This also poses a major economic problem as it requires heat insulation equipment.

Such problems are particularly serious and fatal when transporting acrylonitrile solutions in winter or in cold regions. Not only that, but the boiling point of acrylonitrile is 77.3.
Considering that the acrylonitrile solution is as low as 76,000 tm -H(1), highly toxic and extremely flammable, it must be said that there is a safety problem in maintaining the acrylonitrile solution at a high temperature.

[Problem that the invention seeks to solve]

Therefore, the purpose of the present invention is to prevent the deterioration of a solution of maleimides in 7-acrylonitrile and to make it difficult for maleimides to precipitate from acrylonitrile, thereby making it possible to easily and safely prepare a high-quality, highly concentrated solution of maleimides even at a low temperature. The purpose is to provide a method of transporting or storing at low cost.

[Means to solve the problem]

In order to achieve this objective, the present inventors have conducted intensive studies and found that the deterioration of maleimides in acrylonitrile can be effectively prevented in the coexistence of a polymerization inhibitor, and that the deterioration of maleimides from an acrylonitrile solution can be effectively prevented. The higher the purity of the maleimide, the easier it will be to precipitate near the saturated solubility, but on the other hand, if the maleimide has an average molecular weight of 100 or more, preferably 200 to 100.000, in the 7-crylonitrile solution. By coexisting a compound that has the same properties and is inactive against maleimides and 7-acrylonitrile, it is possible to make it difficult for maleimides to precipitate from an acrylonitrile solution, and to prepare a stable supersaturated solution that can be easily handled even at low temperatures. They discovered that it could be done and completed the present invention.

By adding a polymerization inhibitor and a compound with a relatively large molecular weight to a highly concentrated acrylonitrile solution of maleimides, it is possible to prevent the deterioration of the maleimide in the acrylonitrile solution, and also to prevent the crystallization of the maleimide. The fact that it can be handled stably and safely as a supersaturated solution is completely surprising, and must be said to be a major advance in the handling of such solutions.

That is, the present invention provides an acrylonitrile solution containing a maleimide, which contains a polymerization inhibitor and an average molecular weight of 1 that is inert to the maleimide and acrylonitrile.
This is a method for transporting and storing maleimides, characterized by handling them in the coexistence of 00 or more compounds.

The present invention will be explained in detail below.

Maleimides that can be transported and stored by the method of the present invention include, for example, N-methylmaleimide, N-ethylmaleimide, N-heVsilmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-benzylmaleimide, N- Cyclohexylmaleimide, N-phenylmaleimide, N-nitronoenylmaleimide, N-meth1diphenylmaleimide, N-methylphenylmaleimide, N-carbo1diphenyl7reimide, N-hydroxyphenylmaleimide, N-chlorphenyl? Reimide, N-dichlorophenylmaleimide, N-dichlorophenylmaleimide, N-promphenylmaleimide, N
Examples include, but are not limited to, -dibromphenylmaleimide, N-trichlorophenylmaleimide, N-tribromphenylmaleimide, and the like.

Examples of polymerization inhibitors that should coexist in the acrylonitrile solution include methoxybenzoquinone, p-meth1diphenol, phenothiazine, hydroquinone, alkylated diphenylamines, methylene blue, tert-butylcatechol, tert-butylhydroquinone, zinc dimethyldithiocarbamate, and dimethyl Examples include, but are not limited to, copper dithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionic acid esters, mercaptobenzimidazole, triphenylphosphites, alkylphenols, alkylbisphenols, and hindered phenols. It's not something you can do. The amount used is 0.0001 to 1.0% by weight, preferably 0.001 to 0.5% by weight, based on the acrylonitrile solution of maleimides. The type of polymerization inhibitor is selected in consideration of the type of polymer to be produced, the polymerization method, the initiator to be used, and the like. For example, in styrene resins such as ABS resin and As resin,
- When a polymer with high whiteness is desired as the final product, hindered phenols are effective as polymerization inhibitors.

Although the reason for this is not clear, it is thought that this compound has the effect of effectively suppressing the generation of impurities that color the final product, which are generated during storage or polymerization of a solution of maleimides in acrylonitrile.

Furthermore, the compound to be allowed to coexist in the acrylonitrile solution may be an inert compound that does not react with acrylonitrile or maleimides and has an average molecular weight of 100 or more, preferably in the range of 200 to 100,000.

Specific examples include the following:

(a) An oligomer and/or polymer comprising at least one member selected from the group consisting of acrylonitrile, the maleimides, styrene, methylstyrene, ethylstyrene, butadiene, methacrylic esters, and acrylic esters.

(b) Compounds represented by the following formulas ■ to ■ (wherein R1 and R2 are hydrogen, an alkyl group having 1 to 20 carbon atoms, a phenyl group, a benzyl group, a cyclohexyl group, a pyridyl group, a quinolyl group, and these groups) and halogen substitution, carboxy group substitution, and nitro group substitution.) etc., but are not limited to these.

The layer of the compound used is 0.01-2C11%, preferably 0.01% to 2C11%, preferably 0.01% to 2C, based on the maleimide in the acrylonitrile solution.
It is 1 to 10% by weight.

The effects of the compound vary depending on the type and amount added, but in general, the precipitation temperature of maleimides from an acrylonitrile solution can be lowered over a range of about 5 to 40° C. by adding 1% of the compound.

Addition of 0.01% by weight without vortexing is less effective, and conversely, addition of more than 20% by weight causes problems such as the polymerization reaction not proceeding quickly during polymerization and further impairing the physical properties of the final polymer. be.

Furthermore, if the polymerization inhibitor itself has 100 or more molecular species and it is acceptable to add a large amount to the solution, it goes without saying that the purpose can be achieved by adding the polymerization inhibitor alone. .

It goes without saying that the type and size of the compound are selected in consideration of the type of final polymer formed using the acrylonitrile solution, the polymerization method, the polymerization conditions, and the like.

The temperature at which maleimides are dissolved in acrylonitrile is preferably below the boiling point of acrylonitrile, and since acrylonitrile has a high vapor pressure, it is usually 40°C.
Melting takes place at ~60°C, then -10~50°C
It is handled within the scope of.

As for the dissolution method, basically any method can be adopted, but acrylonitrile may be added to the maleimide and the compound, or the compound and the maleimide may be dissolved in acrylonitrile. The maleimides used at this time may be solid or liquid.

Further, in a preferred embodiment, a method of dissolving maleimides in acrylonitrile containing an acrylonitrile oligomer and/or polymer can be considered, but the method is not limited thereto.

The concentration of maleimides in an acrylonitrile solution is determined by the temperature at which the solution is handled, the amount of the compound added, etc., but the higher the concentration of maleimides in the acrylonitrile solution, the cheaper the transportation cost. Concentration is preferred.

〔Effect of the invention〕

The present invention has been described above, and the advantages obtained by the present invention are as follows.

(1) Maleimides can be easily handled as a liquid without direct contact with the human body, and transportation and storage are simple and safe.

(2) Highly concentrated 7-reimides can be handled stably and safely at low temperatures without precipitation of maleimides.

(3) Since high concentration maleimides can be easily transported and stored, transportation and storage costs are low.

(4) Since high concentrations of maleimides can be handled stably and safely, the solution can be used to obtain R-linear compounds containing maleimides and having a high degree of openness.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 In a 5oId flask equipped with a stirrer and condenser,
200g of N-phenylmaleimide adjusted to the following composition,
100 g of acrylonitrile and 10 Rg of +1-meth1 diphenol were added.

N-phenylmaleimide composition N-phenylmaleimide 99.61 II% 2-anilino-N-phenylsuccinimide 0.3 (molecular weight 266
) N-Phenylmaleimide 0.1 Medic acid (molecule [1191) The water bath temperature was adjusted to bring the internal temperature to 50°C, and the solution was dissolved immediately to give a completely clear yellow acrylonitrile solution.

The saturated dissolution temperature of this solution is 45°C, but no N-phenylmaleimide crystals were observed to precipitate even when the solution was cooled to 25-30°C, and even when vigorously stirred in this temperature range, was also stable.

Furthermore, when the water bath temperature was adjusted and the internal temperature was maintained at 50° C. for 30 days, the clarity of the solution remained unchanged after the holding, and no foreign matter was observed in the solution.

Subsequently, 7-crylonitrile was evaporated from this solution under reduced pressure to obtain bright yellow crystals.

When the purity of this product was measured by liquid chromatography, it was found to be 99.6% by weight, and no change was observed at all.

Example 2 In Example 1, the stabilizer was p-methoxyphenol 10
In addition to rItg, triethylene glycol bis(3(
0.5G of 3-t-butyl-5-methyl-4-hydrocyphenyl)propionate was added. When this solution was cooled, N-phenylmaleimide crystals precipitated for the first time at 25°C.

Note that the saturated dissolution temperature of this solution was 45°C. Furthermore, this solution was stable even when vigorously stirred at 30° C., and no crystals were observed.

Roughly, the water bath temperature was adjusted and the internal temperature was maintained at 50° C. for 90 days, but the clarity of the solution did not change after the holding and no foreign matter was observed in the solution.

Subsequently, acrylonitrile was distilled off from this solution under reduced pressure, yielding bright yellow crystals.

When the purity of this product was measured by liquid chromatography, it was 99.6% by weight, and no deterioration was observed.

(However, the purity was converted to a purity that does not contain stabilizers.) Examples 3 to 13 N-Phenylmaleimide 200Q and acrylonitrile 100Q having the same composition as used in Example 1 and N- When an acrylonitrile solution of phenylmaleimide was prepared and stored at 50°C for 30 days, the results shown in Table 1 were obtained.

Comparative Examples 2 to 4 The precipitation temperature was measured using N-phenylmaleimide having the following composition. The results are shown in Table 2.

N-phenylmaleimide composition N-phenylmaleimide 99.91 [1% anhydrous maleic*o,i (molecular weight 98) Table 2 Furthermore, when the solutions of Comparative Examples 2 to 4 were stored at 60°C for 30 days, the storage The ftI solution, which had been clear, became cloudy and the viscosity of the solution increased, indicating that polymerization had clearly occurred.

Claims (1)

[Claims] (1) An acrylonitrile solution containing maleimides is handled in the presence of a polymerization inhibitor and a compound with an average molecular weight of 100 or more that is inactive to maleimides and acrylonitrile. Transportation and storage methods.